The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference.
Lignans are phenolic compounds widely distributed in plants. They can be found in different parts (roots, leafs, stem, seeds, fruits) but mainly in small amounts. In many sources (seeds, fruits), lignans are found as glycosidic conjugates associated with fiber component of plants. The most common dietary sources of mammalian lignan precursors are unrefined grain products. The highest concentrations in edible plants have been found in flaxseed, followed by unrefined grain products, particularly rye.
Considerable amounts of lignans are also found in coniferous trees. The type of lignans differs in different species and the amounts of lignans vary in different parts of the trees. The typical lignans in heart wood of spruce (Picea abies) are hydroxymatairesinol (HMR), α-conidendrin, conidendrinic acid, matairesinol, isolariciresinol, secoisolariciresinol, liovile, picearesinol, lariciresinol and pinoresinol (Ekman 1979). The far most abundant single component of lignans in spruce is HMR, about 60 percent of total lignans, which occurs mainly in unconjugated free form.
Plant lignans such as hydroxymatairesinol, matairesinol and secoisolariciresinol, are converted by gut microflora to mammalian lignans, enterolactone or enterodiol (Axelson et al., 1982; WO 00/59946). A recent study (Heinonen et al., 2001) shows also that matairesinol, secoisolariciresinol, lariciresinol and pinoresinol glucoside were to be converted to enterolactone.
Lignans have putative beneficial effects on human health. The health benefits obtained with lignan rich diet include (Adlercreutz 1998; Vanharanta et al. 2002):                1) decreased breast cancer risk        2) decreased risk of prostate cancer risk        3) decreased risk for cardiovascular disease risk        
Based on studies on their biological activities, lignans may also suppress immunological overactivity and thus be of use in preventing a immunological disease.
According to our experience, lignans (hydroxymatairesinol, matairesinol and enterolactone) are well absorbed molecules from the gastrointestinal tract. However, as can be seen from Scheme 1 disclosing the structure of certain lignans, the lignans contain hydroxyl groups, and such hydroxyl groups are targets of phase II metabolic reactions (conjugation into glucuronic acid, sulfonate or glutathione conjugates). Especially phenolic hydroxyl groups are likely targets for these reactions.
It is known that metabolites after phase II conjugation reactions are almost invariably pharmacologically inactive. The inactivity results from the inability of conjugated metabolites to penetrate cell membranes and thus be disposited into tissues, but they are rather being rapidly eliminated into the urine (by way of kidneys) or into the intestine (by way of hepatobiliary excretion).
Thus, conjugation is considered as an inactivation process of various molecules, including lignans.